Rinse the bones in cold water to remove blood and bone fragments.

Place in a large bowl of cold water and soak for 8 hours or overnight. While soaking, change the water a couple of times.

Drain the bones and put them into a large stock pot.

Add water until the bones are submerged.

Cover and boil for about 20 minutes over high heat, until it is vigorously boiling.

Remove from the heat. Drain the bones, rinse each bone with cold running water, and drain well.

Wash the pot thoroughly and put the bones back to the clean pot.

Fill the pot with water (I added 6½ quarts water to my 10 quarts pot).

Cover and cook over high heat for about 30 minutes until the water starts boiling.

Reduce the heat to low and simmer for 10 hours.

Open the lid and stir the bones with a wooden spoon.

Fill the pot with water, cover and simmer for 9 hours.

Fill the pot with water again. Increase the heat to medium high heat and cook for 1 hour without the lid.

Remove from the heat. Let it cool down a little bit until you can handle it.

Remove all the bones from the broth and discard.

Strain the broth over a large bowl. Discard the strained bits (or you can eat them).

Let the broth cool to room temperature and refrigerate for several hours or overnight until the thick layer of the fat on the surface is solidified.

Remove and discard the solid fat.

Ladle some hot broth into a bowl and serve with rice, chopped green onion, ground black pepper, kimchi, and other side dishes.